Server SSH Access

This repository automatically distributes "authorized_keys" files to servers.

On a push to this repository, all authorized_keys files are updated on all servers.

Basic understandings

SSH Keys basics: "https://youtu.be/ZKZbPZCnHRE?t=257"

Usage

1. find or create the key you want to add (e.g. ~/.ssh/id_ed25519.pub)
   if you don't have a key yet, you can create one with ssh-keygen -t ed25519 to print the key use cat ~/.ssh/id_ed25519.pub on linux/mac and type %USERPROFILE%\.ssh\id_ed25519.pub on windows

2. add the key to the authorized_keys.<servername> file in this repository (for the server you want to get access to)

3. commit and push the changes to this repository

4. add new host to "/.ssh/config" locally on your machine

   Host <hostname>
       Hostname <hostname>
       User <user>
       Port <port> # optional
   

5. If everything is done right, you should have access without need for password with command ssh user@hostname

Add host

This script connects to the server via SSH with the rootkey to update the authorized_keys file.

For this script to work it needs SSH access to the server. For this the server needs to have the contents of the rootkey.pub in the servers authorized_keys file.

Prepare server

1. You need to have SSH access to the server. Note down the Hostname and the User you want to use.
2. add the rootkey_*.pub from this repository to the server's ~/.ssh/authorized_keys file (in the users home directory)
   connect to the server (via ssh)
   a. if the folder does not exist, use: mkdir ~/.ssh to create the directory and adjust the rights with: chmod 700 ~/.ssh
   b. use nano ~/.ssh/authorized_keys to add the rootkey (exit with ctrl+c, then "y" then press return, afterwards adjust the rights with chmod 600 ~/.ssh/authorized_keys

Configure repository

3. add new host to "config" file

   Host <hostname>
       Hostname <hostname>
       User <user>
       Port <port> # optional
   

4. add host to ".github/workflows/update-all.yml" file
5. push the changes to this repository

Server SSH configuration

6. Now check with your own key if you have access to the server

   ssh <user>@<hostname

7. ONLY CONTINUE IF YOU HAVE ACCESS WITHOUT NEEDING A PASSWORD

8. Now you need to disable password login and root login via SSH

   sudo nano /etc/ssh/sshd_config

   find and change the following lines

   PasswordAuthentication no
   PermitRootLogin no
   

9. restart the SSH service

   sudo systemctl restart sshd